Disk drives are information storage devices that use thin film magnetic media to store data. A typical disk drive includes one or more rotating disk having concentric data tracks wherein data is read or written. As the disk rotates, a transducer (or xe2x80x9cheadxe2x80x9d) is positioned by an actuator to magnetically read data from or write data to the various tracks on the disk. When the disk is rotating at operating speeds, pressure effects caused by air flow between the surface of the disk and an air bearing surface of the head cause the head to float above the disk. In a constant rotation speed disk, these pressure effects can change as the head moves between different radial positions over the disk surface. As a result, the height of the disk head is affected. To maintain optimum device performance, dynamic control of head height is desired.
In general, in one aspect, the invention features a data storage device that includes a head suspension assembly having an attached airfoil. The airfoil is coupled to an active (i.e., movable) element that responds to signals from height control circuitry. In another aspect, the invention features a method of controlling a height of an air bearing surface. The method includes positioning a suspension assembly having an airfoil and an air bearing disk head over a surface of a rotating data storage disk. A position (i.e., angle) of the airfoil can then be dynamically altered to change a distance of the disk head perpendicular to the surface of the disk.
Implementations may include one or more of the following features. The suspension and airfoil can be parts of a head gimbal assembly. The active element can be a piezo-electric transducer or a solenoid that is attached to the airfoil and suspension assembly and is configured to exert a force between the airfoil and a point on the suspension assembly in response to a signal from the height control circuitry The airfoil can have an edge attached to a planar region of the head suspension assembly and its position can be altered by flexing of the airfoil around an axis formed by the edge. The device can include a flexor attached at a forward end of the suspension assembly and an air bearing slider attached to the flexor. The device can also include a disk-type data storage media coupled to a disk rotating motor, and an actuator coupled to the suspension and operable to move the slider between radial positions of a disk media. The device can include positioning control circuitry that provides a signal to the actuator to control a radial position of the slider with respect to the disk media and provides a signal indicative of the radial position to the height control circuitry. The height control circuitry may regulate the airfoil position in response to the radial position signal. The head suspension assembly can include a magnetic data head. The suspension assembly may include a height sensor that can generate a signal indicative of disk head height. The signal may be generated, e.g., in response to a measured thermal change.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.